It's hard to believe that West Australian Premier Colin Barnett was once on the same side as environmentalists in opposing a radical plan from Tidal Energy Australia (TEA) to generate electricity from the giant tides around the West Kimberley town of Derby, albeit for different reasons.

Environmentalists said, and still say, that any benefits from generating power without fossil fuels will be wiped out by the destruction of some of Derby's mangrove ecosystem along with the environmental costs of transmitting centralised power to disparate regional users.

Robin Chapple is the Greens MLC for the Mining and Pastoral Region which takes in the town of Derby, and he's unequivocal in his opposition to the project which sells itself as environmentally friendly.

"I think we need to go back and actually understand that this is not tidal power, this is hydropower. It's damming a creek system and therein lays a number of major problems which in most cases were identified by the EPA (Environmental Protection Authority) as being significant."

Critical to Tidal Energy Australia's plans are that their project will generate continuous power even though the tides naturally cycle over the course of any given week from being amongst the world's largest to an insignificant amount of water movement. A system of barrages and reservoirs built around the tidal creek system north of Derby will allow water to continuously flow through turbines and generate power. But this requires significant modification of the natural creek system which comes at a cost both financially and environmentally which Mr Barnett questioned in 2000 when he was the State's energy minister in the Richard Court Liberal Government.

At the time, minister Barnett was seen as one of the big obstacles that prevented TEA from progressing their ambitious plan which had Howard Government support from then conservation minister Wilson Tuckey. But now the long sought-after state government environmental approvals have been granted by Premier Barnett's Environment Minister, Albert Jacob.

"I think this is quite an exciting proposal because it's a true renewable energy, in fact a base load renewable energy source and quite a significant one." says Minister Jacob.

The Minister says that previous holdups for the project were not because of environmental concerns.

"It wasn't a case of the EPA not having been satisfied. And obviously it's been through this EPA process and they've put out 14 conditions which apply to it. I think some of the delays previously may have been with the proponents themselves." Mr Jacob says.

The EPA's conditions will require TEA to conduct further studies on the impact of their tidal energy power station and transmission infrastructure on threatened communities and species. Federal environmental approvals are yet to be granted.

But a bigger obstacle still could be finding a customer for their electricity. Since TEA first proposed their tidal energy project, new mostly gas-fired power stations have been built for the larger West Kimberley communities and existing electricity supply contracts will run until 2027. TEA had hoped that a James Price Point LNG facility may have provided a customer, but with Woodside's recent decision not to proceed with that project, TEA's Brian Rourke is hunting for a new potential customer for tidal energy.

"There's quite a few smaller mines. There's Ellendale Diamonds out east of Derby. There's quite a few zinc prospects around the area and we're looking at quite a few mining sites." says Mr Rourke.

The challenge will be overcoming uncertainty around the cost of generation using tidal energy and then transmitting this power over potentially long distances to customers at a rate than can compete with conventional power generation.

Finding a customer for the tidal energy power station that is able assure investors of the economic viability will be essential to the realisation of the project. Mr Rourke plans to raise capital for construction by floating his company on the stock exchange in mid 2014.

It's been a long road for Kimberley tidal power generation to get to the point of state government environmental approvals, and there's a long road yet to be travelled before the rise and fall of Derby's King Sound will drive generator turbines. But the local Shire President, Elsia Archer, is ecstatic that the project is one step closer.

"I mean this is huge news for us and I think it's fantastic." she says.

You can listen to Elsia Archer, Robin Chapple and Brian Rourke discuss their views of TEA's project with Vanessa Mills on Kimberley Mornings.

And you can hear Minister Jacob's interview with Natalie Jones for ABC News.